Conventional techniques pertinent to production of pulp molded articles include the one disclosed in JP-B-35-9669, which comprises the steps of inserting a core having an expandable film into a fiber preform with an opening that has been deposited in a papermaking mold through the opening and feeding a fluid into the inside of the film to expand the film whereby the preform is pressed onto the inner wall of the papermaking mold and dewatered.
The above-described method of producing a pulp molded article is suited to mold hollow containers with an opening facing up but unsuitable for producing fiber-molded tubular hollow articles having a bend or a twist.
The technique disclosed in JP-A-52-128412 is known as a conventional method relating to the production of a fiber-molded bent hollow article. According to the technique, an L-shaped molded article is deposited and dewatered by using a set of splits of a papermaking mold joined to form a cavity having two or more openings connecting with the outside and two pressing members inserted into the papermaking mold through the openings. Because insertion and extraction of the pressing members are through the openings of the cavity, the pressing member cannot be inserted into some cavities that are so complicated as to have a plurality of bends. Besides, this technique is difficult to apply to the production of fiber-molded hollow articles with a smaller inner diameter at the opening than the inner diameter at the intermediate portion or fiber-molded tubular hollow articles with a twist.
The technique taught in JP-A-2000-239998 is known for the production of a fiber-molded tubular hollow article having a plurality of openings. The technique comprises separately forming fiber preforms in a plurality of split molds and joining the split molds to unite the fiber preforms into one body thereby to produce a tubular molded article with a uniform thickness. In this regard it has been desired to develop a method of making a fiber-molded tubular hollow article with a uniform thickness in which fiber preforms are united into one body more firmly.
Accordingly, an object of the present invention is to provide a fiber-molded hollow article with a uniform thickness which has a complicated bent configuration and is composed of fiber preforms firmly united into one body, a convenient method of producing the molded article, and an apparatus for producing the molded article.